The royal couple canceled their Christmas travel plans to their residence in Sandringham on Wednesday due to illness, Buckingham Palace said in a statement. It is unclear when they plan to travel again.

"The Queen and The Duke of Edinburgh have heavy colds, and so have decided not to travel to Sandringham today," the statement read.

Queen Elizabeth, 90, is still scheduled to address the nation in her annual Christmas day speech on Sunday.

The news comes after the monarch announced on Tuesday that she was stepping down as patron of 25 organizations in order to reduce her workload. She will be handing over her patronage of certain groups to other members of the royal family including her grandson, Prince William, and Kate Middleton.

The Queen is currently the world's longest-reigning living monarch. But in June, she celebrated Prince Philip's 95th birthday with a sweet portrait by photographer Annie Liebovitz. "He has, quite simply, been my strength & stay all these years," the Queen said of her husband.